Collision Assessment By Offset Ebl - Furuno FR-2105 Operator's Manual

1.18 Collision Assessment by Offset EBL

The origin of the EBL can be placed anywhere with the trackball to enable measurement of
range and bearing between any targets. This function is also useful for assessment of the
potential risk of collision. To assess possibility of collision:
1. Press the EBL ON key to display or activate an EBL (No. 1 or 2).
2. Place the cursor (+) on a target appearing as threatening (A in the illustrated example) by
operating the trackball.
3. Press the EBL OFFSET key on the mode panel, and the origin of the active EBL shifts to
the cursor position. Press the EBL OFFSET key again to anchor the EBL origin.
4. After waiting for a few minutes (at least 3 minutes), operate the EBL control until the EBL
bisects the target at the new position (A'). The EBL readout shows the target ship's course,
which may be true or relative depending on the settings on the RADAR 1 menu.
If relative motion is selected, it is also possible to read CPA (Closest Point of Approach) by
using a VRM as shown below (Figure (a)). If the EBL passes through the sweep origin
(own ship) as illustrated (Figure (b)), the target ship is on a collision course.
5. To return the EBL origin to the own ship's position, press the EBL OFFSET key again.
330
320
310
A
300
290
280
A
270
260
250
240
230
EBL 1
220
210
EBL
200
> 150.3 R<
(a) Evaluating the target ship course in RM
000
VRM 1
350 010
020
340
030
040
050
060
070
1
110
120
130
140
150
VRM
160
190 170 >3.85 NM<
180
320
310
300
290
280
080
270
090
260
100
250
240
230
EBL 1
220
EBL
> 150.3 R<
(b) Target ship on collision course
-1.22-
000
350 010
020
340
330 030
040
050
A
1
A
130
140
210 150
200
160
190 170
180
> 0.00 NM<
060
070
080
090
100
110
120
VRM